Hearing aid



FIG. 1 is a perspective view of the hearing aid;

FIG. 2 is a left side view of the hearing aid;

FIG. 3 is a right side view of the hearing aid;

FIG. 4 is a front view of the hearing aid;

FIG. 5 is a rear view of the hearing aid;

FIG. 6 is a top view of the hearing aid; and,

FIG. 7 is a bottom side of the hearing aid.

The broken lines immediately adjacent the shaded areas represent the bounds of the claim, while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design. 

CLAIM The ornamental design for a hearing aid, as shown and described. 